Police told AFP that a woman, Marcia Valentine, attempted to mow down Jesse James during the incident at the couple's home.

TMZ.com celebrity website reported that the attack took place as Bullock and James' 10-year-old son Jesse Jr looked on.

A spokesman for Orange County police south of Los Angeles confirmed to AFP that the incident occurred after Valentine was discovered lying on the driveway of the couple's home.

"Mr James found the suspect, Marcia Valentine, lying on their driveway," officer Jim Amormino said.

"He asked her to leave, but instead she got into her car and tried to run him over three to four times. We are treating it as assault with a deadly weapon."

Valentine was arrested early Monday and was released on Tuesday after posting bail of 25,000 dollars. She is due to appear in court on May 22.

A spokeswoman for Bullock, 42, confirmed the incident.

"Both Jesse James and Sandra Bullock are fine and it is now in the hands of the authorities," Cheryl Maisel told People.

Bullock, the star of "Speed," "Miss Congeniality" and last year's best picture Oscar-winner "Crash" has suffered problems with stalkers in the past.

In 2006 she won a three-year restraining order against a man she has accused of stalking her across three US states.